1. Field of the Invention
The present invention is related to solid state optical devices and, more particularly, is directed toward injection diode amplifiers and lasers, acousto-optic feedback gratings, diode detectors, and single crystal fibers having cladding for operating as optical/infrared waveguides.
2. Description of the Prior Art
Double-heterojunction diode lasers, amplifiers and detectors have individually been under intensive development. For example, extensive research is being performed on constricted double-heterojunction single-mode lasers and detectors based upon use of gallium arsenide and gallium aluminum arsenide where the percentages of gallium and aluminum are varied. This work has resulted in excellent lasers including the Distributed Feedback Laser. See, for example, the article entitled "Channeled-Substrate-Planar Structure Distributed-Feedback Semiconductor Lasers" by Kuroda et al., Applied Physics Letters, 1978.
Extensive research is also being conducted on the growing of very long single crystal fibers having cross-sections of a few square micrometers. One of the materials which can be grown in single crystal fibers is gallium arsenide and, with the addition of a gallium aluminum arsenide cladding, these fibers become optical or infrared waveguides.
A third area of extensive research involves acousto-optic control of optical signals on integrated optics.
My prior U.S. Pat. Nos. 4,133,612 and 4,138,196 set forth a rotary motion sensor which employs an endless, closed-loop, multiple turn fiber interferometer which takes advantage of the Sagnac interferometer effect. Sagnac demonstrated that light traversing a closed path experiences an apparent path length change when the closed path is rotated about an axis perpendicular to the plane containing the closed path. He demonstrated that the apparent path length increased in the direction of rotation and decreased in the opposite direction.
In my improved embodiment set forth in U.S. Pat. No. 4,133,612, coherent laser radiation is coupled into the fiber interferometer in both a clockwise and counter-clockwise direction and is permitted to traverse the entire interferometer waveguide many times so as to increase the cumulative phase shift due to multiple traversals. Means are provided for coupling the coherent radiation into and out of the fiber interferometer.
With the advent of the above-described technologies, I have recognized that there exists means whereby the input and output coupling of the signals to and from the fiber interferometer can be improved, which would greatly increase the accuracy of the rotational rate sensing device. It is toward achieving this broad object that the present invention is advanced.